Devices, systems and methods employing knitted fabric mulch

ABSTRACT

Knitted fabric mulches are disclosed for use in erosion control, landscaping, irrigation, and growing systems for agriculturalhorticultural purposes. The fabrics incorporate insert strips of paper, metal, plastic, or other material and employ different types of yarn, depending upon the intended purpose. Irrigation tubes and/or seed tapes are incorporated in certain fabrics employed for agriculturalhorticultural purposes.

[ June 10, 1975 United States Patent 11 1 Seith et al.

[54] DEVICES, SYSTEMS AND METHODS 3 777 987 l2/l973 239/542 EMPLOYINGKNITTED FABRIC MULCH $330,067 8/1974 Osborn et al. 239/[45 [75]Inventors: Robert T. Seith, Tuscaloosa, Alum,

Otto M. Bundy, Bradenton. Fla.

[73] Assignee:

Attorney Agent, or FirmRaphael Semmes [22] Filed:

ABSTRACT Related US. Application Data Division of Ser. No. 333,782. Feb.20 I973, Pat No. 3,848.359.

Knitted fabric mulches are disclosed for use in erosion control,landscaping, irrigation, and growing systems [52] Us 239/145; 239/542for agriculturalhorticultural purposes. The fabrics in- 51] Im. AOlg27/00 corpmate insert Strips of Paper metal. Plastic, or [58] Field ofSearch 239/145 542, 266; 47/9 other material and employ different typesof yarn, de-

47/48 5 pending upon the intended purpose. Irrigation tubes and/or seedtapes are incorporated in certain fabrics [56] References Cited employedfor agriculturalhorticultural purposes.

UNITED STATES PATENTS 3.774.850 239/542 9 Claims, 7 Drawing FiguresPATENTEI] JUN I 0 I975 SHEET DEVICES, SYSTEMS AND METHODS EMPLOYINGKNITTED FABRIC MULCH This is a division of application Ser. No. 333,782,filed Feb. 20, 1973, now U.S. Pat. No. 3,848,359.

BACKGROUND OF THE INVENTION This invention is concerned with theprovision and utilization of knitted fabric mulches, the term mulclf asused herein meaning a protective covering spread or left upon the groundto reduce evaporation, maintain even soil temperature, prevent erosion,control weeds, enrich the soil, or to provide an irrigation and/orgrowing system, as will be later described.

Woven jute and synthetic nettings have been used for the control oferosion for several years. The open nettings are too weak to providesufficient soil stabilization, are difficult to handle, and have atendency to tear during laying. The closed nettings are expensive, and,being non-degradable, tend to be lifted by grass growing under thenetting, allowing wind to lift the netting from the ground. Eventuallythe netting must be removed by hand and effective control of erosionceases.

Existing nettings have been employed or suggested for use inapplications such as highway construction and maintenance, landscaping,and strip mine recovery. With the possible exception of certainlandscaping applications, all such uses require a system needing littlemaintenance once the area covered by the netting is planted. It would behighly desirable to have a product which would both degrade enough toallow full development of vegetation and yet provide permanent erosioncontrol. These characteristics are particularly important in thereplanting of strip mine areas. None of the products presently availableprovides a completely satisfactory solution, especially for miningapplications.

U.S. Pat. No. 3,315,408 to Fisher is an example of a prior art wovenfabric intended for the control of soil erosion. Although the patentsuggests the utilization of different types of yarns, includingbiodegradable yarns and tubular or hollow core yarns containing agentsor materials to be released (such as fertilizers, pesticides and weedkillers), the woven fibrous material taught by this patent suffers fromthe deficiencies of woven materials, including limited flexibility andlimitations upon the yarns which may be woven. Moreover, the fabricstaught do not possess sufficient versatility to provide a completeagricultural-horticultural system.

Other types of mulches or ground covers employing sheets of material, ascontrasted with nettings, are disclosed, for example, in U.S. Pat. No.3,205,619 to Henry, U.S. Pat. No. 3,302,323 to Popa, U.S. Pat. No.3,467,142 to Boyle, et al., U.S. Pat. No. 3,511,694 to Lippoldt, et al.,U.S. Pat. No. 3,427,194 to Lippoldt, et al., and U.S. Pat. No. 3,516,196to Lippoldt, et al. The Henry, Popa, and Boyle et al. patents teach theutilization of such sheets for irrigating or fluid distribution. It hasalso been proposed to provide ground cover sheets with seeds,fungicides, fertilizers, insecticides, herbicides, and growth hormones,for example, to facilitate the planting and growth of grass or otherplants. See, for example, U.S. Pat. No. 3,557,491 to Franklin, et al.,and U.S. Pat. No. 3,160,986 to Watson, et al. However, it has not beenpossible heretofore to provide such elements and structures in asatisfactory open-mesh mulch, in particular a mulch having sufficientversatility and other basic characteristics to provide a completeagricultural-horticultural system.

BRIEF DESCRIPTION OF THE INVENTION It is accordingly a principal objectof the present invention to provide improved devices, systems, andmethods which avoid or overcome the aforesaid and other disadvantages ofthe prior art.

A further object of the invention is to provide improved devices,systems, and methods for erosion control, landscaping, andagricultural-horticultural purposes.

Briefly stated, the present invention is based upon the provision andutilization of open-mesh knitted fabrics which may incorporate a varietyof inserts, including, for example, insert strips of paper, metal,plastic or other materials, seed tapes, and irrigation tubes.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be furtherdescribed in conjunction with the accompanying drawings, whichillustrate preferred and exemplary embodiments, and wherein:

FIG. I is a fragmentary perspective view of an embodiment of theinvention incorporating an irrigation tube and a seed tape;

FIG. 1A is an enlarged fragmentary plan view illustrating details of theembodiment of FIG. 1;

FIG. 2 is a diagrammatic perspective view, partially broken away,illustrating the utilization of a mulch of the invention in a growingsystem for grass, for example;

FIG. 3 is a fragmentary sectional view illustrating the manner in whichliquid is supplied to an irrigation tube incorporated in the invention;and

FIGS. 4, 5 and 6 are fragmentary diagrammatic perspective viewsillustrating the utilization of different types of mulches in accordancewith the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, andinitially to FIG. 1 thereof, the present invention employs an open-meshknitted fabric, generally designated by reference numeral 10, which mayincorporate a plurality of inserts, such as the strips 12. The basicfabric incorporating inserts may be manufactured by the so-called VEEVtechnique, as described, for example, in U.S. Pat. No. 3,507,130 toMarks, et al. As is well known, the knitted fabric may be considered ascomprising longitudinally connected loops defining wales andtransversely connected loops defining courses. Different types ofknitting stitches, such as the jersey stitch or the full tuck stitch,may be employed. In at least one direction, such as the direction of thecourses, the fabric has considerable stretchability, as contrasted withthe non-stretchability of woven fabrics. In the fabrics employed in thisinvention, a wide variety of knitting yarns may be used, depending uponthe physical properties and durability required for the end useapplication. The yarn fibers, which may be used in deniers ranging from50 to 850, for example, may include one or more of the followingmaterials:

Acetate Acrylic Anidex composed of at least 500? b weight of one or moreesters of a monohydric alco ol and acrylic acid. Fiber in which thefiber-forming substance is glass.

Glass Cotton. linen. jute and other natural fibers Metal Fiber in whichthe fiber-forming substance is stainless steel.

Modacrylic Fiber in which the fiber-forming substance is any lon chainsynthetic polymer com oscd of less than 851 but at least 3592 by weighto acrylonitrilc units.

Nylon h polyamide ha ing recurring amide groups as an integral part ofthe polymer chain (there are (1 carbons per molecule. hence thedesignation Nylon 6). Nylon as Same as Nylon 6 except it is thepoly-amide from two different compounds each containing 6 carbons permolecule.

Olefin Fiber in which the fiber-forming substance is any long chainsynthetic polymer composed of at least 859': by weight of ethylene.propylene. or other olefin units.

Polyester Fiber in which the fiber-forming substance is any long chainsynthetic polymer composed of at least 85% by weight of an ester of adihydric alcohol tercphthalic acid. Fiber composed of regeneratedcellulose as well Rayon as fibers Composed of regenerated cellulose inFiber-forming substance is any long chain synthetic which substituentshave replaced not more than i592 of the hydrogens of the hydroxylgroups. Fiber-forming substance is any ion chain synthetic polymercomposed of at feast 80% by weight of vinylidene chloride units.

Fiber in which the fiber-forming substance is a long chain syntheticpolymer comprised of at least 859': of a segmented polyurethane.

Saran Spandex Triacetaie groups are acetylated. the term triacetate maybe used as a generic description.

The inserts 12. which in general may be of much greater width than theknitted yarns. extend along parallel paths. preferably between andparallel to the wales and perpendicular to the courses. The inserts areinter 4U skipped), and inserts need not be placed between every 45 pairof wales (some pairs of wales may be skipped to provide open spaces).The inserts may be formed of materials such as paper. metal foil. orplastic. or combinations of the same, depending upon the end applicationof the invention. Paper inserts may have selected 50 degrees ofbiological degradation. the following being a list of suitable papers.which are listed in order of increasing rate of resistance to biologicaldegradation:

1. Unsized. unhydrated. kraft composed of at least 55 80% hardwood fiber2. Southern bag papers standard grades 3. Recycled waste paper 4. Papertreated with mold'inhibiting chemicals 5. Paper same as 4 but coated onone or two sides 60 with a barrier coating.

in most instances. the insert strips will be opaque. and in someinstances. (as where it is desired to reflect heat). the insert stripswill be light-reflecting. The strips cover a major portion of the areaof the fabric. 5

In accordance with the invention. other types of inserts may also beincorporated in the fabric. all at the Fiber in which fiber-formingsubstance is cellulose acetate. Where not less than 92'7r of thehydroxyl point of manufacture. Thus, as shown in FIG. 1, one or moreirrigation tubes 16 may extend along paths parallel to the insert strips12 and be interlaced with ele ments of the fabric. such as the crosslinks 14. The irrigation tubes are preferably formed of eo-extensivejuxtaposed strips 18 and 20 which are sealed to each other along theirlongitudinal edges 22, the tube being normally collapsed to a flat statewhich permits it to be readily inserted into the fabric and to be rolledup with the fabric for storage. Typically, the irrigation tube may beformed of Tyvek spunbonded olefin. which is a sheet structure composedof very fine plexifilaments of linear polyethylene. This is a porousmaterial having a pore size of 5 or 6 microns, for example. a Gurley airporosity (sec/lOOM k psi) of l3, and an MVTR (g/24 hrs/M of between 800and 1.000. The porous strip material. which may be /3 inch wide. forexample. may be heat sealed at the longitudinal edges to form a tubewhich is V2 inch diameter when expanded by internal pressure. Theirrigation tube may be covered by an opaque (black) polyethylene andpaper laminated strip or an aluminum foil and paper laminated strip 24which serves as a water-impervious and/or heat-reflective protectivecovering overlying the tube.

FIG. 3 illustrates the manner in which the irrigation tubes may besupplied with liquid from a header pipe 25 connected to a liquid supply(not shown). An adapter tube 28 fixed to and extending transversely fromthe header pipe 25 fits within the opened end of the irrigation tube 16,which is secured thereto by a wire or plastic tie 30. The header may bepart of a liquid distribution system, which may include a water pump,filters, meters, valves. chemical supply tanks. and chemical pumps, allof which cooperate to supply liquids to the irrigation tubes at thedesired rate and concentration.

A further type of insert which may be incorporated in the knitted fabricis a seed tape 26. The seed tape may be composed of a pair of strips ofwater soluble material, such as polyvinyl alcohol material, sealed alongtheir edges and having seeds secured therebetween at spaced locations.as shown at 28 in FIGS. 1 and 1A. Alternatively, the seed tapes may beformed of biodegradable paper strips to which the seeds are attached bymeans of a suitable water-soluble or biodegradable adhesive. As willappear hereinafter, the insert strips 12 may themselves be seed tapes.The seed tapes may incorporate plant hormones. nutrients, biologicaladditives, fertilizers, pesticides, fungicides, etc. which may be placedwithin or upon the tapes as spots where the seeds are located ordistributed generally in the tapes.

H6. 2 illustrates the utilization of a mulch of the invention in alandscaping application. The knitted fabric incorporates a series ofirrigation tubes 16, and the insert strips 12, which may be of unsizedkraft paper to promote rapid biological deterioration, may have grassseed 28 randomly attached to the lower side thereof, as by a nutrient(dextrine) glue which increases the rate of deterioration. The mulch,which may be supplied in rolls of any convenient width and length, isspread over the area of the ground to be treated and is secured theretoby staples and by anchoring edges of the mulch material in shallow slotsor trenches. The irrigation tubes are connected to a liquid supplyheader (not shown in FIG. 2). As water is applied to the system, thepaper deteriorates allowing germination of the seeds. The mesh, whichmay be formed of non-degradable knitting yarns, remains in place aftergermination and sinks into the plant root structure to provide permanenterosion resistance. By using specially treated or coated papers, therate of deterioration can be controlled over a span of several years, ifdesirable.

FIG. 4 illustrates a type of mulch in accordance with the inventionwhich may provide a growing system for lettuce or cabbage, for example.The mulch material has a total width of 60 inches, for example, withthree inches at each longitudinal edge placed under soil for anchoringpurposes. The mulch incorporates a pair of irrigation tubes 16, whichmay be 27 inches apart and equally spaced from the longitudinal edges.and four seed tapes 26, which may be thirteen and a half inches apartwith the outermost seed tapes spaced equally from the longitudinaledges. The seeds may be three inches apart on the tapes but the plantsmay later be thinned to twelve inch spacing. in FIG. 5 a mulch ofsimilar overall dimensions is shown incorporating three irrigation tubes16 and eighteen seed tapes 26 having seeds spaced apart of the order oftwo inches. Such a mulch is suitable for the growing of carrots, forexample. in FIG. 6 a mulch having the same overall dimen sions is shown,but incorporating a single irrigation tube 16 along the longitudinalcenter line and having holes 32 through the fabric for the planting oftomato or squash plants, for example. The holes may be 2 inches indiameter, spaced 24 inches apart longitudinally and staggered back andforth with respect to the irrigation tube 16.

From the foregoing it is apparent that an agriculturalhorticulturalgrowing system of the invention comprises a knitted fabric of yarns oryarn-like elements and a plurality of inserts interengaged or interlacedwith such elements. The insert strips include strips of paper, forexample, which may have a broad selection of properties depending uponthe end use application, irrigation tubing, water soluble or degradableseed tapes, and various cover strips, which may be plastic or metalmaterial, for example, to protect various insert elements. and also tocontrol temperature or even to measure pH or other physical/chemicalcharacteristics. As a whole the purpose of this system is to modify. inthe most desirable manner, the soil/air environment wherein a plant orgrass grows or develops and provide a mechanism either for anchoringgrass in place or harvesting a commercial crop. The system may be usedfor (l) landscaping including lawn or grass development, highway erosioncontrol and planting, and the growing of ornamental crops, (2) miningincluding strip mine recovery (growing stabilizing erosion controlelements in hostile environments), modification of soil chemicalproperties, and recovery of land subjected to chemical defoliation, and(3) food production including the growing of vegetables or grains, forexample.

In the production of food crops, for example, by utilization of theinvention, the selective placement of seed tapes and irrigation tubingin the knitted fabric, the inclusion of treated mulch paper in theremaining warp areas, and the selection of a proper knitting yarnprovide a total system capable of unique control over the growing andharvesting process results. The advantages of the growing system of theinvention over conventional methods include higher marketable yield,higher quality crops, substantial reduction in water requirements (dueto trickle irrigation at the points where the water is best utilized bythe plants and due to reduced evaporation), reduction of saltaccumulation in the soil, reduction of the need for fertilizers andchemicals, reduction of root damage due to cultivation, the provision ofprecise plant spacing and increased uniformity of growing environment,the production of earlier yields, and the provision of resistance towind and water erosion. The inclusion of seed tapes and irriga tiontubing in a knitted open-mesh mulch which prevents erosion and reduceswater evaporation produces a synergistic effect, increasing crop yieldswhile reducing water requirements.

The advantages of the invention are also clearly evident in theapplication to strip mine reclamation. One of the most difficult areasto replant is a mine where high sulfur content coal has been strippedfrom the surface. Residual sulfuric acid creates a most hostile soilenvironment. By using encapsulated seeds on tapes and a buffered oralkaline water through the irrigation tubes, these soil acids can beneutralized, resulting in immediate plant growth and high survivalrates.

The utilization of knitted fabrics provides greater flexibility andconformity to the surface of the ground than has hetetofore beenpossible. Yarns may be used which are not capable of being woven, withconsequent savings in cost and increase in versatility. Paper insertcharacteristics may be varied to meet a variety of end use requirements,so that the system may be tailored to the particular application. Forexample, where the application is rapid lawn development with minorerosion control thereafter. a biodegradable mesh knitted fabric may beemployed together with a paper that will degrade rapidly. For a ditchliner. however. where permanent protection is required. a non-degradableyarn and a permanent paper. such as a polyethylene coated paper may beused.

Typical mulches in accordance with the invention may incorporateknitting yarns and paper insert strips in the following combinations.which are merely for the purpose of example:

40 pound kraft paper 840/600 polypropylene yarn (typical fabric weightper square yard: 3 ounces.

comprising 1.529 ounces of paper and L472 ounces of yarn) Gulf StatesPaper Corp. spec. 42/4020 green bag paper 420 denier polypropylene yarnGulf States Paper Corp. standard 42 pound bag paper 840 denierpolypropylene yarn Gulf States Paper Corp. sized 30 pound asphaltingkraft paper 420 denier polypropylene yarn Gulf States Paper Corp.polyethylene coated mulch paper 840 and 420 denier polypropylene yarn 55pound uncoated mulch paper 840 denier polypropylene yarn 55 poundmold-proof paper coated with /2 mil medium density polyethylene on eachside 1050 polypropylene yarn.

While preferred embodiments of the invention have been shown anddescribed, it will be apparent to those skilled in the art that changescan be made in these embodiments without departing from the principlesand spirit of the invention, the scope of which is defined in theappended claims.

The invention claimed is:

l. A mulch comprising an open-mesh knitted fabric constituted by amultiplicity of knittedly interconnected longitudinal and transverseyarn elements, said fabric having at least one irrigation tube betweenlongitudinal yarn elements and interleaved with transverse yarn elementsof said fabric. said irrigation tube being substantially wider than saidyarn elements.

2. A mulch in accordance with claim I. wherein said tube comprises apair of co-extensive strips sealed together along longitudinal edgesthereof and normally juxtaposed, so that the tube is collapsed untilpressurized internally.

3. A mulch in accordance with claim 2, wherein at least one of saidstrips is porous.

4. A mulch in accordance with claim 3, further comprising a protectivestrip covering one side of said tube.

5. A mulch in accordance with claim 4, wherein said protective strip isWater-impervious.

6. A mulch in accordance with claim 4, wherein said protective strip isopaque.

7. A mulch in accordance with claim 4, wherein said protective strip islight-reflecting.

8. A mulch in accordance with claim 1, further comprising means forcoupling one end of said tube to a supply of liquid to be dispended fromthe tube.

9. A mulch in accordance with claim 1, there being a plurality of saidtubes interleaved with courses of said fabric along parallel paths.

1. A mulch comprising an open-mesh knitted fabric constituted by amultiplicity of knittedly interconnected longitudinal and transverseyarn elements, said fabric having at least one irrigation tube betweenlongitudinal yarn elements and interleaved with transverse yarn elementsof said fabric, said irrigation tube being substantially wider than saidyarn elements.
 2. A mulch in accordance with claim 1, wherein said tubecomprises a pair of co-extensive strips sealed together alonglongitudinal edges thereof and normally juxtaposed, so that the tube iscollapsed until pressurized internally.
 3. A mulch in accordance withclaim 2, wherein at least one of said strips is porous.
 4. A mulch inaccordance with claim 3, further comprising a protective strip coveringone side of said tube.
 5. A mulch in accordance with claim 4, whereinsaid protective strip is water-impervious.
 6. A mulch in accordance withclaim 4, wherein said protective strip is opaque.
 7. A mulch inaccordance with claim 4, wherein said protective strip islight-reflecting.
 8. A mulch in accordance with claim 1, furthercomprising means for coupling one end of said tube to a supply of liquidto be dispended from the tube.
 9. A mulch in accordance with claim 1,there being a plurality of said tubes interleaved with courses of saidfabric along parallel paths.